This research program project includes the following studies: 1. Normal Development of Nervous System in Humans, including detailed studies of: (a) The normal sequence of development of the central and peripheral nervous systems, skull, and vertebrae in staged embryos, emphasizing light and electron microscopic, and histochemical methods. (b) The development and growth of the corpus callosum and pyramidal tracts. (c) Histological and radiological features of the normal growth and maturation of the fetal spinal cord and vertebral column. 2. Normal development of Nervous System in Non-Human Primates, including: (a) Staging of primate embryos. (b) Study of normal development, as in 1a above, including the development of the eye. (c) Radioautographic studies of placodes and caudal proliferation center. 3. Teratological Studies. These will include the development of experimental models, using teratogenic agents in pregnant monkeys: (a) Malformations of the nervous system, skull, and vertebrae. (b) Defects of the nervous system associated with limb defects caused by Thalidomide. 4. Computerization of Data Storage and Retrieval (feasibility study). 5. Planning for Clinicopathological Studies.